In the movies, especially the old school ones that were all about overcoming adversity and coming out on top against all odds. There was often a scene in the film where the hero or heroine finally got themselves together and started preparing for whatever the main event of the movie would be.
And rather than showing countless hours of a person learning a new skill, failing, getting back up, failing and then finally mastering whatever it was that they were trying to learn. Movie makers made a montage. Every single step taken into account and then the whole thing was cut into smaller more manageable pieces. The pieces were then made to fit together in a continuous flow that gave the viewer an idea of just how hard the lead of the movie worked to achieve their goal.
Derek like movie montages, they saved a lot of time. But in all his years of watching movies, Derek had never in his life thought that he would see a movie montage live.